Composite pouring tube



Oct. 18, 1966 J. w. YATES 3, 7

COMPOSITE POURING TUBE Filed April 19, 1965 -86 IN VE N TOI'? JAMEsWewou YA-ras WZZ/PESS: BY J g 4 all M H 2- United States Patent3,279,003 COMPOSITE POURING TUBE James Weldon Yates, Glen Ellyn, Ill.,assignor to Amsted Industries Incorporated, Chicago, Ill., a corporationof New Jersey Filed Apr. 19, 1965, Ser. No. 449,116 Claims. (CI. 22-79)The present invention relates to a composite pouring tube.

The pouring tube of the present invention is particularly adapted to usewith casting iron and steel in which the molten metal involved is ofextremely high temperatures and is highly deleterious to equipment andmaterials used in connection therewith.

The invention has further particular adaptation to pouring tubes forpressure pouring where the pouring tubes are immersed in the moltenmetal to be cast.

Pouring tubes for use in casting iron and steel are normally composedof, or include as a substantial component thereof, refractory materialwhich is capable of withstanding attacks by the molten metal. Refractorymaterial is relatively brittle and weak, and it has the furtherdisadvantage that it is porous, enabling, at least in certain instances,air and gases to penetrate therethrough and into the molten metal beingcast, resulting in bubbles in the casting which, of course, constitutedefects.

A broad object of the present invention is to provide a pouring tube foruse in pressure pouring iron and steel which incoporates a steel shelltherein which serves the dual purpose of providing strength to anotherwise weak tube, and forms an impermeable membrane to the passage ofair and gases through the wall of the pouring tube.

Such a steel shell has certain disadvantages, the most serious of whichit its liability to attack by molten iron and steel. It has anotherdisadvantage in that it has a high coefiicient of expansion relative torefractory and other materials normally used in pouring tubes of thisgeneral nature.

Another and more specific object of the invention therefore is toprovide a composite pouring tube which includes refractory and othermaterial capable of withstanding attack by the molten metal, whichincorporates a steel shell therein for the purposes stated, and furtherin which the steel shell is incorporated in such a manner as to protectit from attack by the molten metal, and to compensate for differentialin coefficients of expansion of the steel and refractory material.

Still another and specific object of the invention is to provide acomposite pouring tube of the character just referred to wherein thesecurement between the steel shell and the refractory materials islocated principally adjacent one end of the tube whereby to accommodaterelatively greater expansion and contraction between the steel shell andrefractory material throughout a greater portion of the length of thetube, as contrasted with providing such securement throughout the lengthof the tube.

Other objects and advantages of the invention will appear from thefollowing detailed description taken in conjunction with the accordingdrawings wherein:

FIGURE 1 is a small scale view showing the use of a pouring tube inconjunction with a ladle and mold in a pressure pouring arrangement; and

FIGURE 2 is a large scale longitudinal sectional view of such a tubeembodying the features of the present invention.

Referring now in detail to the drawings, attention is directed first toFIGURE 1. A pressure pouring tube is "Ice shown at 10 mounted inconjunction with a ladle 12 in which the lower end of the tube extendsinto the ladle to a point adjacent the bottom thereof. The ladle issuitably disposed, such as in a pit 14 closed by a cover 16 whichsurrounds the pouring tube and also serves as a means for mounting andsupporting the pouring tube in the desired position. Air or other gas isprovided from a suitable source (not shown) and transmitted through aconduit 18 into the interior of the pit. Upon the air or other gasreaching the necessary pressure it forces the molten metal 20 in theladle upwardly through the pouring tube and into a mold 22 placed abovethe tube and having an ingate passage in communication with the pouringtube. After the mold is filled, the supply of air is cut off and themold removed and replaced by another mold in repeated steps until themolten metal in the ladle is substantially completely poured.

Such pouring tubes are of various sizes according to the installationsin which they are used and the bigger sizes present correspondinglygreater problems. Because the lower end of the tube must extendsubstantially to the bottom of the ladle, the problems are intensifiedbecause a greater portion of the tube is subjected both inside and outto molten metal in the ladle, for at least portions of the pouringoperations.

The tube 10 made according to the present invention and shown in detailin FIGURE 2 includes a head assembly 24 which constitutes the means forsupporting the tube in position by the cover 16. This head 24 ispreferably made up of a plurality of steel parts including an innerferrule 26 having a radially inwardly extending flange 28. The upperportion 30 of this ferrule is of reduced diameter forming a shoulder 32on which is disposed a ring 34 secured in place by cap screws 36inserted in holes therein and threaded into the ferrule 36. An asbestosgasket 37 is interposed between this ring and the shoulder 32, butpreferably a vent space 40 is provided between the ring and the outercylindrical surface of the extension 30. The radially outer portion ofthe ring 34 constitutes the part that directly engages the cover 16 ofthe pit for supporting the tube in position. A collar 42 is fitted abovethe ring 34 and has a radially inwardly directed flange 44 overlying andengaging the upper end of the ferrule 26. Surrounding the foregoing is aholding ring 44 having a radially outwardly directed flange 46.

The ferrule 26 is provided with one or more diagonal holes 48communicating between its inner surface above the flange 28 and itsouter surface opening through the reduced portion 30. Communicating withthe holes 48, or the vent space 40, or both, are one or more vent holes50 formed in the ring 34 and extending generally radially outwardly.These vent holes open into an annular recess 52 in the ring which mateswith another annular groove 54 in the holding ring. These two groovesform an an nular channel which communicates with the exterior through avent space 56 between the ring 34 and the holding ring 44, both aboveand below the channel, this vent space then communicates with anothervent space 58 between the collar 42 and holding ring 44. The foregoinghead assembly 24 in general has been known, and does not enter into thepresent invention per se, except that it provides venting spaces forcooperation with the remainder of the pouring tube, the remainder of theconstruction of the pouring tube in this respect including at leastcertain features of the invention.

The remainder of the pouring tube other than the head assembly isindicated at 60 and is mounted on and carried by the head assembly 24.This pouring tube includes an inner refractory element 62 extending thefull length of the intended ultimate pouring tube, being preferablyflush at its upper end with the upper end surface of the head assembly.This inner tube or liner 62 in itself is of known construction, beingpreferably of refractory material. It withstands attack by molten ironand steel as much as any other material, but it is fragile andrelatively weak. It is also porous and permeable to gas, to an extent,through the wall thereof.

The pouring tube structure includes .a tubular steel shell 64 insurrounding relation to the inner tube 62, and spaced therefrom as willbe referred to again hereinbelow. This steel shell is mounted to thehead assembly 24 preferably by abutting it to the lower end surface ofthe ferrule 26 and welding it thereto as indicated at 68. The steelshell terminates at its lower end above the lower end of the remainderof the tube, as determined by the lower end of the tube 62, the detailsof which will be referred to again hereinbelow.

A quantity of cement 70 of known kind is placed in the annular space 66in the upper end of the tube and permitted to harden. It may extend ashort distance downwardly terminating above the diagonal holes 48, andbelow the cement 70 is a quantity of sand 72 filling the space betweenthe cement to a point adjacent the lower end of the steel shell. Thissand may be put in place by inverting the tube relative to the positionshown, after placement of the cement 70, and then pouring in the sand,the sand being cured by a known process. A fine mesh cloth screen 74 maybe placed over the holes 48 to hold the sand in the space intended.

After the sand is put in place a gasket 76 is put in the annular space66 in contact with the sand. This gasket may be of asbestos and O-ringin shape. Then another quantity of cement 78 is put in the space fillingit nearly to the end of the steel shell, in the position then assumed bythe tube at the top.

A plurality of rivets 80 are secured to the outer surface of the steelshell as by inserting them in holes in the shell or welding themthereto. These rivets are preferably round headed and are approximatelyeight in number and distributed at random over the surface of the steelshell. These rivets form the principal means anchoring the outerprotective sheath 82 of refractory material to the steel shell, asreferred to again hereinbelow. The rivets are located principally at thelower end of the tube, providing anchoring between the steel tube andthe outer sheath at the lower portion of the tube enabling the upperportion of the sheath to migrate longitudinally of the tube, as alsodescribed hereinbelow. The rivets preferably are located inapproximately the lower third of the length of the pouring tube,although the exact area of this distribution is not critical.

A wrapping 82 of heat insulation material is placed on the outer surfaceof the steel shell, which also accommodates changes in the physicaldimensions of the various elements resulting from differential expansionof the steel and other elements. This wrapping 82 is of refractorymaterial and in its original form is a wet and highly pliable sheet. Itis wrapped around the steel shell in the area desired, and through thecourse of the construction :placed in a mold for applying the refractorysheath 84. Such a mold may be a simple cylindrical container receivingthe lower end of the tube, the lower end of the inner tube 62 resting onthe bottom of the mold. The space in the mold surrounding the tubestructure is filled with a refractory material of known type, which isin suitable plastic form. It is put in such a manner as to fill theannular space 66 below the lower end of'the cement 78 in completelysurrounding relation to the lower end of the steel shell and the lowerturned-in end of the Wrapping. It will be observed that the refractorymaterial forming the sheath 84 completely envelopes the rivets 80 andthe portions of the wrapping thereover to provide the desired physicalanchorage between the steel shell and the sheath.

Preferably the sheath 84 terminates at its upper end below the headassembly 24, being of suitable, length to extend the full depth of anylevel of molten metal in the ladle so as to prevent contact by themolten metal with that portion of the tube above the sheath.

If desired, as an optional construction, a sleeve 88 of material similarof the wrapping 82 may be applied directly to the inner tube 62 betweenthe gasket 76 and adjacent to but below the ferrule 26.

Bubbles of air and other gases forming in the molten metal have longbeen recognized as a difiiculty encountered in this type of casting. Airentrapped in the pores of the inner tube 62 as well as other elementsincorporated in tubes heretofore, expands upon the molten metal movingupwardly in the pouring tube in engagement with the inner tube 62. Thisair must, of course, have an escape passage and in the absence of otherescape passages would flow through the wall of the inner tube 62 andinto the passage thereof and into the molten metal, forming defects inthe castings. the pouring tube is the superatmospherlc pressuredeveloped in the pit 14. This pressure is of extremely high value andair heretofore has been forced through the wall of the pouring tube,with detrimental effects mentioned.

The steel shell 64 in the present instance provides an impermeablemembrane in the pouring tube preventing the passage of air entirelythrough the wall of the pouring tube. The air in the pores of the sand72 is permitted to escape through the vent holes '48 and other ventpassages outwardly thereof, as described above. Air trapped in the poresof the inner tube 62 may also escape through these vent passages.

The coeflicient of expansion of steel is substantially greater than thatof the other elements in the construc-. I

tion of the pouring tube and, particularly, the refractory material ofthe sheath 84. As the steel shell is heated it elongates at a ratesubstantially greater than the refractory sheath. However, because ofthe position of the rivets 80 adjacent the lower end of the tube, thesheath is permitted to migrate, relatively speaking, up and down thesteel shell, thus eliminating or greatly minimizing any damage to any ofthe elements, particularly the sheath which is relatively brittle.complete freedom in the upper portion of the sheath.

Expansion of the steel shell, of course, takes place radially and thisexpansion is at a greater rate than that i of the sheath. However, theinstallation of the wrapping 82 compensates for this differential to asubstantial degree. This wrapping also offers a degree of accommodationto the relative movement in longitudinal direction between the steelshell and refractory sheaths.

The inner tube 62 and the sheath 84 both provide a high degree of heatinsulation to the steel shell, being 1 particularly effective withrespect to that portion of the tube actually immersed in the moltenmetal. Above the sheath where the molten metal does not directly contactAnother source of air or gas in This migration is permitted outer layerand having its lower end completely enveloped in the wall and confinedtherein against exposure therethrough, and means for positivelyanchoring the outer layer of refractory material to the steel shell,said lastmentioned means including a plurality of projections secured tothe steel shell and extending radially outwardly therefrom and embeddedin the refractory material of the outer layer, said projections beingcontained within the lower portion of the pouring tube.

2. A composite pouring tube for use in casting iron and steel andadapted for insertion of its lower end into the molten metal therefor,comprising a wall including an inner layer and an outer layer ofrefractory material, a steel shell embedded in the wall between theinner and outer layer and having its lower end completely enveloped inthe wall and confined therein against exposure therethrough, saidcomposite pouring tube including a head assembly with said steel shellwelded directly thereto, said inner layer of refractory material beingporous and the head assembly being provided with vent passagescommunicating with the pores in the inner layer of refractory materialand extending to the exterior of the head assembly.

3. A composite pouring tube for use in casting iron and steel andadapted for insertion of its lower end into the molten metal therefor,comprising a wall including an inner layer and an outer layer ofrefractory material, a steel shell embedded in the wall between theinner and outer layer and having its lower end completely enveloped inthe wall and confined therein against exposure therethrough, the steelshell and inner layer of refractory material being of such relativediameters as to provide an annular space therebetween, said annularspace being filled to the greater extent by sand, the tube beingprovided with vent passages communicating with the pores in the sand andin the inner layer of refractory material and extending to the exteriorof the pouring tube.

4. A composite pouring tube for use in casting iron and steel andadapted for insertion of its lower end into the molten metal therefor,comprising a wall including an inner layer and an outer layer ofrefractory material, a steel shell embedded in the wall between theinner and outer layer and having its lower end completely enveloped inthe wall and confined therein against exposure therethrough, the steelshell and inner layer of refractory material forming an annular spacetherebetween, and a layer of resilient heat insulating materialsurrounding said inner refractory layer in direct engagement therewithand throughout the greater portion of the length of said steel shell,said space, except as limited by said layer of heat insulating material,being filled at least in major portion with sand.

5. The invention set out in claim 3 wherein said sand terminates shortof both the upper and lower end of the pouring tube, and a quantity ofcement is interposed in said space at each the upper and lower end andoperative for confining said sand in said space.

6. The invention set out in claim 5 wherein an asbestos gasket isinterposed between the lower end of the sand and the cement therebelow.

7. The invention set out in claim 6 wherein the inner layer ofrefractory material extends downwardly beyond the lower end of the steelshell, the cement at the lower end terminates downwardly short of thelower end of the steel shell, and the outer layer of refractory materialextends beyond the lower end of the steel shell and engages the outersurface of the inner layer of refractory material, completely envelopingthe lower end of the steel shell and engaging the lower end of thecement at that location.

8. A composite pouring tube for use in casting iron and steel andadapted for insertion of its lower end into the molten metal therefor,comprising a wall including an inner layer and an outer layer ofrefractory material and a steel shell embedded in the wall, and a layerof resilient heat insulating material interposed between the steel walland outer layer of refractory material.

9. The invention set out in claim 8 wherein the layer of heat insulatingmaterial is applied directly to and engages the steel shell.

10. The invention set out in claim 9 wherein the layer of heatinsulating material extends from the lower end of the steel shell whereit is turned inwardly over the lower end of the steel shell to the upperend of the steel shell, and the outer layer of refractory materialterminates upwardly below the upper end of the steel shell.

References Cited by the Examiner UNITED STATES PATENTS 1,407,569 2/1922Pedersen 249l35 X 2,843,646 7/1958 Conant 161-207 X 2,847,739 8/1958Sylvester 2269 3,054,155 9/ 1962 Zickefoose 22209 3,201,837 8/ 1965Sylvester 22209 X FOREIGN PATENTS 9,475 2/ 1895 Switzerland.

I. SPENCER OVERHOLSER, Primary Examiner.

E. MAR, Assistant Examiner.

8. A COMPOSITE POURING TUBE FOR USE IN CASTING IRON AND STEEL ANDADAPTED FOR INSERTION OF ITS LOWER END INTO THE MOLTEN METAL THEREFOR,COMPRISING A WALL INCLUDING AN INNER LAYER AND AN OUTER LAYER OFREFRACTORY MATERIAL AND A STEEL SHELL EMBEDDED IN THE WALL, AND A LAYEROF RESILIENT